Boiler construction



Sept. 25, 1928. I 1,685,388

R. E. WHITE BOILER CONSTRUCTION Filed Dec. 15, 1923 8 Sheets-Sheet 1Sept. 25, 1928.

1,685,388 R. E. WHITE BOILER CONSTRUCTION Filed DEC- 15, 1923 8Sheets-Sheet 2 Sept. 25, 1928.

1,685,388 R. E. WHITE BOILER CONSTRUCTION Filed Dec. 15. 1925 sSheets-Shet s Sept. 25, 1928.

R. E. WHITE BOILER CONSTRUCTION 8 Sheets-Sheet 4 Filec} Dec. 15, 1923Sept. 25, 1928.

R. E. WHITE BOILER conswnucnou' Filed Dec. 15, 1.923 3 Shees-Shet 5 QQQSept. 25,1928.

R. E. WHITE BOILER CONSTRUCTION B Sheets-Sheet 6 I Filed D60. 15, 1923mum w Sept. 25, 1928.

R. E. WHITE BOILER- CONSTRUCTION Filed Dec. 15, 1923 8 Sheets-Sheet 7Sept. 25, 1928. 1,685,388

R. E. WHITE BOILER CONSTRUCTION Filed Dec. 15, 1923 8 Sheets-Sheet 8 7 mss s" 5 Qyflvenw Patented Sept. 25, 1928.

UNITED STATES PATENT OFFICE.

RAYMOND E. WHITE, OF CHICAGO, ILLINOIS, ASSIGNOR TO TUBAL BOILERCOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

BOILER CONSTRUCTION.

Application filed December li, 1923. Serial No. 680,804.

My invention relates to a novel form of boiler and the method of andmeans for constructing the same.

While I shall describe .in the following specification a specificembodiment, namely, a drumless water tube sectional type of boiler, itis to be understood that this is merely for purposes of illustration andthat the invention v is not limited to such form alone. However, W Iwish to call attention to the fact that my present invention ispeculiarly adapted to a boiler section, or to a boiler, or, in fact, acontaining vessel of any kind in which there is no great disparitybetween the sizes of the connected tubes or passageways. The inventionis adaptable to banks of 'tubes,'or boiler sections, or any kind of heattransfer apparatus,

pressure containers and the like.

Referring to the accompanying drawings illustrating a preferred mannerof practicing my invention Figure 1 is an elevational view of one of theblank sheets employed in making 511p a boiler section; I I

Fig. 2 is a similar view showing two of these sheets welded togetheraround their perimeters to form a closed envelope, the

light lines indicating the marginal weld;

Figures 3 and 4c are longitudinal sectional and end elevational views ofa typical form of'die mechanism in. which the metal is'expandedoutwardly between these. lines of welding; v A

Fig. 5 is a side view of a section made in ac:

cordance with the steps illustrated in Figures Fig. 6 is a fragmentaryview showing the bottom connection to the water manifold;

Fig. 7 illustrates the blank sheet employed in another practice of myprocess;

Figures 8 and 9 are side elevational and edge views respectivelyof thislatter sheet after folding;

Fig. 10 is a side elevational view of the blank after it has been weldedaround the edges to form a closed envelope, and after the steamconnection has been welded between the side walls of the envelope;

Fig. 11 illustrates in light lines the lines of contact maintainedbetween the side Walls during the expanding operation carried on inapparatus of the type shown in Figs. 3 and l;

Fig. 12 is a side view of one form of boiler blank as employed inanother performance of my process;

Fig. 16 is a similar view, indicating by dotted lines the profile of thesection and the lines of contact between which the passageways arebulged outwardly in the plate;

Fig. 17 is a more or less diagrammatic showing of die mechanism in whichthe blanks are subjected to pressure to bulge out the passageways;

Fig. 18 is a sectional view through two blanks that have been subjectedto the above expanding operations, these blanks being ready for oininginto a section unit;

Fig. 19 is a sectional view through a boiler setting, illustrating atypical design of boiler section as constructed by my invention;

Fig. 20 is another sectional view through the same at right angles toFig. 19;

Fig.21 is a transveise sectional view of'the boiler, and

Fig. 22 illustrates another design of boiler section produced by myinvent-ion assembled.

in a circular type of boiler.

In carrying out one process of manufacturing a boiler according to myinvention, two sheet metal plates 21 are first cut to approximately thesize and general profile of the completed boiler section. These sheetsare then ,matched and welded together aroundtheir perimeters, asindicated in light "lines at 22. This welding is preferably performedaccording to the Gefei process of seam welding, employing the electricroll-step method. In

the step of welding the two sheets together, a

nipple or plug connect-ion 23 is welded between the sheets at the uppercorner, where it will be in line with a steam outlet conduit of thesect-ion. If desired, the water connection may be employed instead Theresult is a metallic envelope having integrally united edges and anipple fitting welded therein through which fluid pressure may enter theenvelope.

This envelope unit is now subjected to the expanding operation, whereinthe circulating tube areas and the header-areas of the comwith recesses32 corresponding to the bulged circulating tube and header areas in thecompleted section. The envelope is, of course, so matched with respectto these recesses 32 that the bulged tube and header areas will occur inthe proper places in the envelope. The lower forming die 27is preferablyheated, as by providing longitudinal burner openings 3- into whichextend burner tubes 35. .21)

These burner tubes are supplied with fuel from suitable burner nozzlesdischarging into the tubes. The desirability of heating the dies and thesheet metal envelope is dependent upon the gauge of metal being workedand the depth of the draw necessary in the expanding operation. \Vithrelatively light gauge materials, the expanding operation can beperformed with the dies and the materialcold.

A high pressure fluid, such as high pressure superheated steam, orwater, is now forced into the envelope through the nipple connection 23.This pressure will swell or expand the metal in the two walls of theenvelope out into the upper and lower die recesses 32 for forming thecirculating tube and header areas. The flat die surfaces 33 intermediatethe parallel recesses 32 (which form the inclined circulating tubes)retain the intervening web portions between these tube areas insubstantially the same plane as the original sheet, so that. theopposite web portions of both sheets can be subsequently weldedtogether. The two walls of the envelope need not be rigidly clampedtogether between the tube areas during this expanding operation; and, infact, it is pieferable to hold the sheets in such relation that they canslip on each other in the expanding operation, so that the metal can bedrawn from all portions ofeach sheet and a uniform distribution andattenuation of the metal secured. Irrespective of whether or not thedies are forced together under any pressure, it is necessary that anexceedingly strong frame or other supporting structure be provided forholding the dies together against the very large outward pressureexerted through the walls of the envelope, tending to separate the dies.

Where steam is employed as the expanding fluid, the high temperature ofthe steam will assist the lower heated die 27 in heating the two wallsof the envelope.

The envelope or section, after the completion of'the expandingoperation, is illustrated in Fig. 5. While, of course, any preferredarrangement of circulating tubes and headers may be shaped in thesection, I have shown a circulating arrangement which I consider hasnumerous advantages over present day boiler sections. It is opportune toremark that the present method permits of innumerable paths and circuitsfor the water and steam in each section, to meet the fancy of any steamengineer, without materially increasing the cost of the section.I-leretofore, the practice of subdividing a header into a-plurality ofsections and of forming devious paths for the circulating water andsteam was impracticable because of the very high expense of forming andwelding these circulating tubes and headers together at various anglesand in-close proximity. In the form shown, the outer header isconstructed of outer and inner sections 25 and 26, which give a verylarge header area without increasing the thickness of the boilersection. Similarly, the rear header is constructed of outer and innerheader areas 37 and 38. These co-operating header areas are, in eachinstance, connected by cross channels 39, arranged at any desired pointsfor establishing cross communication between the header sections and thecirculating tubes 40. The

for connection to the mud-drum of the boiler,"

as I shall hereinafter describe.

The next step in the process is to weld the two walls of the envelopetogether upon all the partition lines between the tubes and headers.This welding is preferably preformed according to the Gefei process ofseam welding, employing the electric rollstep method; electric spotwelding may, of course, be employed in lieu of the above method, but Ifind the roll-step method to be preferable because of its greaterrapidity and the evenness of the seam. All of the joining lines orsunken areas 42 are welded together by this process, both between thecirculating tubes 40 and between the diiferent portions of the headers.The ends of the welded lines 42 are preferably reinforced againstseparation by performing a pressure spot weld at each end of each line,as indicated at 43. The diameter of each of these spot a greater area ofmetal for providing ample reinforcement. Another expedient forreinforcing the ends of the seam welds is to drill these ends and rivetin suitable rivets where the spot welds are now shown. This rivetreinforcement of the endsof the seam weld mav be employed in conjunctionwith spot welding or without. For example, the end of each line of seamwelding may be spot welded, as first described, and this spot we dedarea then drilled for the reception of the rivet. This would integrallyunite the two walls of the envelope around the rivet hole. A rivetreinforcement of the ends of the lines of welding is shown in Fig. 19.

The header areas and 37 and the endmost tubes 36 and 40 may be expandedout to the marginal weld 22, which circumscribes the edges of thesheets; or thes header and tube areas may be set inwardly considerablyfrom the marginal weld 22, for the purpose of performing a second innermarginal weld 22 around the outline of these header and tube areasduring the process of welding the intermediate lines 42. IVhen thissecond in-' ner marginal weld 22' is employed, the projecting flange orweb and the outer weld 22 are preferably-trimmed off around the entireperimeter of the section. The advantage of this latter method is thatthe marginal weld is subjected to no strain or attenuation of metalduring the expanding operation,

and furthermore, the metal which is drawn in the shaping of these outerheader and tube areas has a relatively free sliding motion for an evendistribution of the metal, the outer marginal weld 22 being spacedconsiderably from where the greater portion of this metal is drawn.

' The next step is to complete a feed water connection with the lowerleg 41 of the rear header. As shown in Fig. 6, this lower leg 41 is outoff to open up the bottom of the header; if the header is slightlycrimped or distorted. this lower end is restored to cylindrical form bythe insertion of a suitable shaping tool. A tubular drift is then forcedup into this cylindrical 1eg,'and is securely welded therein, such as bya welding fillet 45 around the lower edge of the leg 41, or by.

spot welding or seam welding the leg 41 and the drift 4% together. Thelower end of this tubular drift is tapered inwardly on a sphericalcurvature, as indicated at 46, and this spherical end seats on a conicalseat 47 formed in the upper end of a connecting nipple 48. This nipple48 is welded to the top of a muddrum or feed water header 49, havingcommunicatipn therewith through the port 51 cut in the top of the drum49. The spherical end 46, seating on the conical face 47, securesapproximately a line contact therewith. For holding surfaces 46 and 47together against the pressure prevailing in the section, a relativelyfixed wedge-like plate 52 is extended transversely through theconnecting tube 44,

being passed through directly opposite slots cut in the tube. This plateis welded in these slots to integrally unite the plate with the tube 44and to seal the tube around the plate to hold the steam pressure. Theends of the .plate 52 project from the drift tube 44, and

hooking over each of these ends is an eye bolt 53. These two eye boltsextend down and. pass through apertures in theends of a saddle block 54,engaging under the drum 49 and receive nuts 55, by which the sphericalsurface can be drawn down into rigid engagement with the conical surface47. It will be observed that the section is quickly releasable from themud-drum 49 by merely unscrewing the nuts 55 sufficiently to allow theeye bolts 53 to be cleared from the upper shoulders of the plate Thesteam connection attaching to the upper steam outlet nipple 23 will be,hereinafter described in a description of a typical boiler setting builtup of my improved boiler sectlons.

A modification of the foregoing method is illustrated in Figures 7 to 11inclusive. According to this method, the blank is cut with twodiagonally disposed portions which form both walls of the metallicenvelope. In folding the two halves of the blank together a tubularconduit or enlargement 56 is formed along the lower diagonal edge of theenvelope, as shown in Figures 8 and 9. After the completion of thisfolding operation the edges of the blank are welded together around thesides and top. as illustrated at 22 in Fig. 10 and as described in thepreceding embodiment. Instead of folding the blank along the bottom edgeit can, of course, be folded along one of the upright edges so that thetubular conduit will form a front or rear header, such arrangement beingillustrated in Fig. 19. Referring again to Fig. 10, the ends of thetubularconduit 56 are pressed together and welded in the above weldingoperation. Thereafter'the envelope is put through the same step ofexpanding the tube and header areas between dies 27 and 28 by theapplication of an internal fluid pressure, as described of Figures 1 tofi'inclusive. This method is particularly adapted to the use of heavynickel steel sheets, and when using this material, it is desirable toheat the dies and the sheets. In the formation of the passageways in themetallic envelope, the rear headers 37 and 38 and the front headers 25and 26 are placed in communication with the ends of the lower tube orpassageway 56. This latter tube is in closest proximity to the fire andconstitutes a water circulating tube wherein the cold water firstreceives its high temperature. By forming this passageway in the foldingof the blank there are no projecting flanges, rivets or other extraneousmetal which might be subject to local overheating because of itsimmediate proximity to the fire.

This is a desirable construction when using heavy sheets or whereriveting is essential. Boiler codes still exist which make riveting aprerequisite in this type of boiler section. In such event the joininglines 42 between tubes and headers are drilled after the expandingoperation for receiving rivets 57 as shown in Fig. 12. The marginal weld22 is reinforced by rows of rivets 57. The partitions or joining linesmay be seam welded by the roll-step process and then drilled andriveted; this giving the tightness of joint secured by the weld and the"combined strength of the welded joint and the riveted joint. However, itis within the scope of my invention to dispense entirely with thewelding between the circulating tubes and headers by riveting the wallsof the envelope together along the partition lines between the tubes andheader areas after these tubes and header areas have been formed. Amarginal weld 22 around the entire perimeter is desirable in allembodiments of the invention because of the more eli'ective closureagainst leakage that it a fi'ords.

Feed water connection is made through atubulardrift 4.4 which is forcedup into the bottom of the outer rear header 25. The two walls of thesection are preferably welded and riveted together on both sides of saiddrift,

and the draft is preferably welded in the end of the header. The driftmay be connected to the mud-drum of the setting in substantially thesame manner as described of Fig. 6.

In Figures 15 to 18 inclusive I have shown a modified process involvinga slightly different sequence of steps. Each envelope comprises twoblanks 58 which are separately formed, as 1 shall now describe. Beforeany of the welding operations are performed thereon, each blankisinserted between the upper and lower members59 and 61 of a hydraulicor screw press. 'The perimeter of the blank is clamped between thesemembers and a leather gasket 62 is preferably interposed between theblank and the upper clamping member 59 to provide a steam tight seal.The lower clamping member 61 is a forming die into which the blank isadapted to be expanded, having recesses 32 in the face thereofcorresponding to the front and rear headers and the inclined circulatingtubes. Steam or other fluid under pressure is admitted through pipe intothe chamber 63 above the blank 58. This fluid expands the metal downinto the recesses 32 to produce the bulged conduit portions 64 shown inFig. 18. The blank may be heated during this expanding operation. as byapplying heat to the lower die member 61. Obviously. when higlr pressuresteam is employed as the medium for expanding or shaping the metal thetemperature of this steam itself will bring the blank up toa relativelyhigh heat.

After the two opposing blanks have been formed. they are matched asshown in Fig.

18. and thereupon the operation of joining the two blanks together isbegun. The perimeters of the sheets are seam welded together and thecontacting faces of the sheets between the tubeportions 64 are joinedtogether by welding or riveting, or both,- substantially as described ofthe two preceding embodiments. The steam connection 23 is welded betweenthe sheets in communication with the upper end of the rear header orwith the steam outlet connection 36 during the welding operation.

As shown in Figures 13 and 14, the main group of circulating tubes 40may be of circular, elliptical, or irregular section. \Yheu the rearheader area is thicker than the front header, as shown in Fig. 22, itmay be desirable to form the rear ends of the circulating tubes ofelliptical section, as shown in Fig.

.13, so as to have these elliptical ends merge gradually into thegreater-thickness of the rear header. Each tube is then graduallytapered back into circular section towards the sections in the boilersetting they are preferably staggered vertically, as shown in Figures 13and 20. so that vertical flue area between the sections will bedefiected through a sinuous path to bring the products of combustionintocontact with the under and upper sides of each tube 40. Another methodof breaking up the straight line or column flue between the sections isillustrated in Fig. ll. Here each circulating tube 4 0 is of relativelyshallow depth on one side and relatively deep on the other. thisrelation alternating between successive-tubes along the section.

y This is secured by forming relatively shallow depression in one wallof the section or envelope and a relatively deep depression in 1 theother wall of the envelope, to secure a passageway which is somewhatoffset with respect to the vertical plane of the envelope. In thesetting of the sections. these offset connecting tubes are staggeredbetween sections so that the deeply projecting side of one circulatingtube is opposite the shallow side of the circulating tube in the nextsection, whereby circulating tubes overlap vertically and break up anycolumn effect between the sections.

It will be observed from the foregoing that the two walls of theenvelope can be united by seam welding. spot welding or riveting, eithersingly or in any combination of these. The riveting may be confined toreinforcing the ends of the lines of seam welding, as shown in Fig. 19,or may be extended entirely alongthe lines of joining betweentheenvelope walls, as shown in Fig. 12. \Vhere the riveting is used inconjunction with seam welding along the lines of joining. the seamwelding is made sufficiently wide to accommowith any of the processesdisclosed in Figures 1 to 18 inclusive, and then riveting the walls ofthe envelope together along the partition lines between the tubes andconduit areas, instead of welding the partition lines together. Theperimetral edges of the section may also be riveted together, butirrespective of whether these edges are riveted or not, I consider itadvantageous to weld these edges so of the section. The one essential ofthe partition joining between the walls of the envelope is that ofproviding ample strength to prevent any separation of these walls overan extended area. It will be apparent that if a weld lets go internallyit merely results in the side of the boiler section bulging outwardlyinthis immediate area.

The step of heating the envelope, or the blank thereof in highly heateddies during the expanding operation, such as illustrated in Figures 3and 4, is desirable when working nickel steel sheets, but is notessential with certain other metals, and metals of relatively lightgauge. Also, it is not essential to perform the operation of drawing thetube and header areas of the sheets before the partition lines betweenthe tubes are welded together, but this sequence is preferable, as thedistribution of metal is made more uniform.

Figures 19, 20 and 21 illustrate my improved boiler sections in atypical boiler setting. The several steam generating sections aregrouped in parallel relationship with the rear headers along the rearwall 78 of the boiler setting. It will be observed that this design ofboiler section has a front secondary header 79 and a rear secondaryheader 81, the former of which connects with an interme diate cluster ofcirculating tubes 82, and the latter of which connects with the otherends ofthese tubes and with the lowermost circulating tubes 83. Thus thehigh rate of steam format-ion of the lowermost group of tubes is notinterfered with by the upper and less active circulation. Freer steamingresults. The several sections have connection with the common feed waterheader or mud drum 49 in the manner illustrated in Fig. 6. The boilerenclosure is preferably built up of front, side, rear and to walls ofsheet metal 84, having a covering 0 heat refractory material 85. Figures19, 20 and 21 also illustrate just one of the ramifications of myinvention in the construction of the feed water preheaters oreconomizers 87. Each of these preheat ers is constructed of a sheetmetallic envelope having upper and lower headers 88 and 89 connected bya plurality of vertical connecting tubes 91. The welding of the marginsof this envelope and the expanding of these headers and connecting tubeswill be obvious from the preceding description. Separate economizerunits are placed across the front wall and both the side walls of theboiler setting, and co-operate with the abutting rear headers of theboiler sections in forming a combustion chamber circumscribed by watercontaining, heat absorbing walls. The solid heat absorbing surfaceinterposed by each of these economizer sections forms a very effectiveheat barrier against outward loss of heat through the walls of theboiler setting. The interconnection of these economizer Sections will beobvious to one skilled in the art. The upper end of each boiler sectionhas suitable connection through the coupling 92, connecting with thesteam outlet fitting 28 with an individual superheating loop 93. Theother end of each of these superheating loops connects through adetachable coupling 94 with a common steam collection drum 95 extendingacross the top of the boiler setting.

Fig. 22 illustrates the application of my invention to boiler sectionsof the type used in circular boilers, such as are disclosed in Vins lowapplication Serial No. 344,355, patented 95 March 23, 1926, PatentNumber 1,577,549. These boiler sections are illustrated in this .figurein horizontal section, and it will be noted that each section comprisesa relatively large outer header 96 and a series of smaller inner headers97. The envelope is preferably formed by folding a single sheet along avertical edge of the section, preferably the outer edge, so that thelarge outer header 96 can be largely produced by the folding operation.This reduces the attenuation of the metal resulting from deep draws-inproximity to the outer header, The inner vertical edge, the othermarginal edges and the joining lines between the tubes and the headersare welded together as before described. The circulating tubes 98 taperfrom the outer header 96 to the group of inner headers 97. The taperedform of the section has particular co-operation with the circulardisposition of the sections in a round boiler. For example, the outerheaders 96 may be placed in substantially contacting relation to form anouter water wall; one

or more groups of the inner headers 97 may be likewise engaged inabutting relation, particularly where a two pass boiler is desired. Theintermediate circulating tubes may be slightl narrower toprovideupwardly extending file areas between'the section.

In the operation of any of the preceding embodiments there is no need ofmaintaining a definitely fixedwater level, but in preference a levelwill be maintained at about the dash and dot level indicated in Fig. 12.In operation the circulation will be upwards in the front or innerheaders, the water cast upwards in these headers being caught in theopen mouths of the inclined circulating tubes above the water level andflowing back through these tubes in thin sheets in ideal condition forrapid steam formation. From the rear ends of these tubes the waterprecipitates down in the rear header areas, from whence it circulatesforwardly again through the lower group of circulating tubes. As aresult of this circulation, a hydrostatic balance will he maintained inoperation with the level higher in the front header areas than in therear. Any uneven expansion tending to develop because of unequaltemperature above and below the water level will be opposed by thestrength of the two solid sheets of metal, reinforced by. the expandedtube areas between the. sheets. i

By forming two front header areas, or by forming a separate channel upalongside the front header for the lowermost tubes. a much improvedsteam freeing action vis obtained. These multiple header areas provide agreater area and more numerous paths for the separation of the steam.The multiple header areas shorten the lengths of the circulating tubescompared to the aggregate areas of these headers. These shortercirculating tubes are an advantage in that they free'the steam generatedtherein more readily than do longer tubes which tend to blow the en- Giltire water content of the tube by the trapping of the steam therein.

By the present construction the headers are much more effective asheating surfaces. By splitting up one header into a plurality ofchannels the aggregate area of header wall exposed to the heat isincreased and all particles of the water and steam are brought closer tothese heated walls. The present construction also permits of a greaternumber of sections being inserted in a given fur nace area than withprior sections of the same height and width, because of the fact thatthe headers are not so thick as in prior constructions, but arepreferably of only slightly greater thickness than the tubes so that thesections can be placed closer together. This larger number of sectionsprovides a greater baffling efiecton the products of combustion becauseit splits up the gases into a larger number of strata. and-the closespacing of the sections permitted by the relatively shallowheadersresults in a close spacing of the heating surfaces and narrow gaschannels.

The greater area of heating surrace in each section by reason of themarginal fins. the in.- tervening web portion between the tubes andthesectionalized construction of the headers result in a higher heattransfer capacity in each section, and the larger number of sectionsgive a considerably greater total heating area for the entire boiler.

I do not intend to be limited to the particulars herein shown anddescribed, as it will be obvious that my invention may be practiced indifferent ways and by difierent means within the general scope of theteaching herein disclosed.

I claim: a

1. A boiler section constructed of two sheet metal walls andcomprising aplurality of circulating tubes, a pair of inner headers com- .municatingwith said tubes, and a pair of outer headers communicating with saidtubes.

2. A boiler section constructed of two sheet metal walls and comprisinga plurality of circulating tubes. a first inner header communicatingwith said tubes. :1 second inner header disposed substantially in theplane of said tubes and said first inner header and communicating withsaid first inner header, a first outer header communicating with saidtubes, and a second outer hhder disposed substantially in the plane ofsaid tubes and said first outer header.

In witness whereof, I hereunto subscribe my name this 14th day ofNovember, 1923.

RAYMOND E. WHITE.

